The Bytown Museum Youth Council recently hosted guest speaker, Saara Mortensen, archivist from the Ottawa Jewish Archives to learn about the history of photography and techniques for determining the age of a photo.

Photography was made commercially viable in 1839, but it was essentially invented multiple times using a variety of different processes. Identifying these different processes by the materials used and the deterioration of the photograph can assist with dating the object.

Early processes to create "photographs" include camera obscuras and pinhole cameras, which formed images that could be traced over to create likenesses. In 1727, J. Schulze accidental creates the first photosensitive compound by mixing chalk, silver, and nitric acid in a flask. The solution darkened when exposed to sunlight. People were able to use photosensitive paper to create likenesses, but permanence of the image posed a problem. One of the first people to capture an image permanently was Louis Daguerre.